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Dairy farming practised in the Sahara 7000 years ago
IN BRIEF
Simon Lailvaux
THE lizards of Croatia fight like cats and dogs: they brawl even though they belong to two distinct species that don’t compete with each other for food or breeding rights. The Dalmatian wall lizard (Podarcis melisellensis) spends most of its time on the ground under vegetation or on low rocks, while the neighbouring sharpsnouted rock lizard (Dalmatolacerta oxycephala) lives on higher rocks. Simon Lailvaux of the University of New Orleans in Louisiana tested each species’ territoriality by capturing Dalmatian wall lizards and placing them in the territories of other Dalmatian wall lizards, or of sharp-snouted rock lizards. He then repeated the test but moved the sharp-snouted rock lizards instead. Whichever lizard owned the territory was generally more aggressive than the intruder. But to Lailvaux’s surprise, the Dalmatian wall lizards were more aggressive towards sharpsnouted rock lizards than towards their own kind (Journal of Zoology, http://doi.org/hzr). “That’s really weird,” he says, given that the species look different and have distinct diets. It is possible that the two once competed, but have now adapted to distinct habitats, says Lailvaux. This suggests the fights he saw may be “ghosts of competitions past”.
16 | NewScientist | 23 June 2012
Breast could be best for blocking HIV BREAST milk is starting to look like a potent HIV-fighter. An unknown component of breast milk appears to kill HIV particles and virusinfected cells, as well as blocking HIV transmission in mice with a human immune system. Even if babies born to HIVpositive mothers avoid infection during birth, around 15 per cent contract HIV in early childhood. Since the virus can get into milk, breastfeeding was one suspect. To investigate further, Angela Wahl at the University of North Carolina at Chapel Hill and her
colleagues created mice with human bone marrow, liver and thymus tissues that all became infected with HIV if the mice were given an oral dose of the virus. However, if the rodents were fed breast milk containing HIV, the virus wasn’t transmitted (PLoS Pathogens, DOI: 10.1371/journal. ppat.1002732). Previous research had hinted that breast milk might have antiviral properties, but it was unclear if it would prevent HIV transmission. “We have shown that milk has an intrinsic innate
ability to kill HIV,” says J. Victor Garcia, who supervised the work. The hunt is now on for the mysterious ingredient in breast milk that inhibits the virus. If it can be identified, it might even be used to prevent other forms of HIV transmission, such as sexual transmission. So why do some breastfed babies born to HIV-positive women contract the virus, if breast milk doesn’t transmit HIV? It’s possible that suckling on cracked nipples may expose babies to virus in their mother’s blood. ESO
Angry lizards love a good fight
For new stories every day, visit newscientist.com/news
The milky way to farm in the Sahara THE Sahara is hardly the land of milk and honey today, but it used to be very different. Rock paintings showing farmers with cattle are found in the area, but putting precise dates on when they were painted is difficult. Now Julie Dunne of the University of Bristol, UK, and colleagues have discovered milk residue on pottery shards from the Takarkori rock shelter in the Libyan Sahara, in layers known to be between 7200 and 5800 years old. “The Sahara was quite a bit greener then,” Dunne says. “There were lakes, grasslands and a wide variety of animal life ranging from cattle to crocodiles and hippos.” Storing milk in pots suggests it was being cured into cream or yogurt, which the lactoseintolerant prehistoric people would have been more likely to be able to digest, says Dunne. The findings are evidence that milk played an important role in the diet of the prehistoric inhabitants of the region and confirm that dairy farming emerged in this area long before crop farming and sedentary living (Nature, DOI: 10.1038/nature11186).
Runaway is star of cosmic whodunnit A MÉNAGE A TROIS turned ugly, an innocent victim and a fugitive fleeing the scene: this all helped to unravel how a superfast star got its speed. One of just a few known runaway stars, the Becklin-Neugebauer (BN) object is fleeing the centre of the Orion nebula at 30 kilometres per second, and no one knows why. A popular theory is a past interaction with a nearby massive protostar. But Jonathan Tan and Sourav Chatterjee of the University of Florida in Gainesville suggest an alternative idea. They think the runaway BN object invaded a tight
embrace between a pair of stars in Orion, known as theta-1C, creating an unstable threesome. This ejected the star of lowest mass – the BN object. The researchers simulated all possible outcomes of such a threesome: in some cases, the BN object fled at 30 kilometres per second. Next, they calculated seven properties of the simulated, leftover binary system, and found that they matched theta-1C (arxiv.org/ abs/1203.0325v3). Tan presented the results at the American Astronomical Society meeting in Anchorage, Alaska.
Simon Lailvaux
THE lizards of Croatia fight like cats and dogs: they brawl even though they belong to two distinct species that don’t compete with each other for food or breeding rights. The Dalmatian wall lizard (Podarcis melisellensis) spends most of its time on the ground under vegetation or on low rocks, while the neighbouring sharpsnouted rock lizard (Dalmatolacerta oxycephala) lives on higher rocks. Simon Lailvaux of the University of New Orleans in Louisiana tested each species’ territoriality by capturing Dalmatian wall lizards and placing them in the territories of other Dalmatian wall lizards, or of sharp-snouted rock lizards. He then repeated the test but moved the sharp-snouted rock lizards instead. Whichever lizard owned the territory was generally more aggressive than the intruder. But to Lailvaux’s surprise, the Dalmatian wall lizards were more aggressive towards sharpsnouted rock lizards than towards their own kind (Journal of Zoology, http://doi.org/hzr). “That’s really weird,” he says, given that the species look different and have distinct diets. It is possible that the two once competed, but have now adapted to distinct habitats, says Lailvaux. This suggests the fights he saw may be “ghosts of competitions past”.
16 | NewScientist | 23 June 2012
Breast could be best for blocking HIV BREAST milk is starting to look like a potent HIV-fighter. An unknown component of breast milk appears to kill HIV particles and virusinfected cells, as well as blocking HIV transmission in mice with a human immune system. Even if babies born to HIVpositive mothers avoid infection during birth, around 15 per cent contract HIV in early childhood. Since the virus can get into milk, breastfeeding was one suspect. To investigate further, Angela Wahl at the University of North Carolina at Chapel Hill and her
colleagues created mice with human bone marrow, liver and thymus tissues that all became infected with HIV if the mice were given an oral dose of the virus. However, if the rodents were fed breast milk containing HIV, the virus wasn’t transmitted (PLoS Pathogens, DOI: 10.1371/journal. ppat.1002732). Previous research had hinted that breast milk might have antiviral properties, but it was unclear if it would prevent HIV transmission. “We have shown that milk has an intrinsic innate
ability to kill HIV,” says J. Victor Garcia, who supervised the work. The hunt is now on for the mysterious ingredient in breast milk that inhibits the virus. If it can be identified, it might even be used to prevent other forms of HIV transmission, such as sexual transmission. So why do some breastfed babies born to HIV-positive women contract the virus, if breast milk doesn’t transmit HIV? It’s possible that suckling on cracked nipples may expose babies to virus in their mother’s blood. ESO
Angry lizards love a good fight
For new stories every day, visit newscientist.com/news
The milky way to farm in the Sahara THE Sahara is hardly the land of milk and honey today, but it used to be very different. Rock paintings showing farmers with cattle are found in the area, but putting precise dates on when they were painted is difficult. Now Julie Dunne of the University of Bristol, UK, and colleagues have discovered milk residue on pottery shards from the Takarkori rock shelter in the Libyan Sahara, in layers known to be between 7200 and 5800 years old. “The Sahara was quite a bit greener then,” Dunne says. “There were lakes, grasslands and a wide variety of animal life ranging from cattle to crocodiles and hippos.” Storing milk in pots suggests it was being cured into cream or yogurt, which the lactoseintolerant prehistoric people would have been more likely to be able to digest, says Dunne. The findings are evidence that milk played an important role in the diet of the prehistoric inhabitants of the region and confirm that dairy farming emerged in this area long before crop farming and sedentary living (Nature, DOI: 10.1038/nature11186).
Runaway is star of cosmic whodunnit A MÉNAGE A TROIS turned ugly, an innocent victim and a fugitive fleeing the scene: this all helped to unravel how a superfast star got its speed. One of just a few known runaway stars, the Becklin-Neugebauer (BN) object is fleeing the centre of the Orion nebula at 30 kilometres per second, and no one knows why. A popular theory is a past interaction with a nearby massive protostar. But Jonathan Tan and Sourav Chatterjee of the University of Florida in Gainesville suggest an alternative idea. They think the runaway BN object invaded a tight
embrace between a pair of stars in Orion, known as theta-1C, creating an unstable threesome. This ejected the star of lowest mass – the BN object. The researchers simulated all possible outcomes of such a threesome: in some cases, the BN object fled at 30 kilometres per second. Next, they calculated seven properties of the simulated, leftover binary system, and found that they matched theta-1C (arxiv.org/ abs/1203.0325v3). Tan presented the results at the American Astronomical Society meeting in Anchorage, Alaska.